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Commit cde164ae authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Arnaldo Carvalho de Melo
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tools lib fs: Add helper to find mounted file systems 



In preparation for adding tracefs for perf to use, create a findfs
helper utility that find_debugfs uses instead of hard coding the search
in the code. This will allow for a find_tracefs to be used as well.

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20150202193552.735023362@goodmis.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 5693c926

tools/lib/api/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -9,11 +9,13 @@ LIB_H= 
LIB_OBJS=



LIB_H += fs/debugfs.h

LIB_H += fs/findfs.h

LIB_H += fs/fs.h

# See comment below about piggybacking...

LIB_H += fd/array.h



LIB_OBJS += $(OUTPUT)fs/debugfs.o

LIB_OBJS += $(OUTPUT)fs/findfs.o

LIB_OBJS += $(OUTPUT)fs/fs.o

# XXX piggybacking here, need to introduce libapikfd, or rename this

# to plain libapik.a and make it have it all api goodies

tools/lib/api/fs/debugfs.c

+7 −44
Original line number Diff line number Diff line
@@ -20,58 +20,21 @@ static const char * const debugfs_known_mountpoints[] = { 


static bool debugfs_found;



/* verify that a mountpoint is actually a debugfs instance */



static int debugfs_valid_mountpoint(const char *debugfs)

{

	struct statfs st_fs;



	if (statfs(debugfs, &st_fs) < 0)

		return -ENOENT;

	else if ((long)st_fs.f_type != (long)DEBUGFS_MAGIC)

		return -ENOENT;



	return 0;

}



/* find the path to the mounted debugfs */

const char *debugfs_find_mountpoint(void)

{

	const char * const *ptr;

	char type[100];

	FILE *fp;

	const char *ret;



	if (debugfs_found)

		return (const char *)debugfs_mountpoint;



	ptr = debugfs_known_mountpoints;

	while (*ptr) {

		if (debugfs_valid_mountpoint(*ptr) == 0) {

			debugfs_found = true;

			strcpy(debugfs_mountpoint, *ptr);

			return debugfs_mountpoint;

		}

		ptr++;

	}



	/* give up and parse /proc/mounts */

	fp = fopen("/proc/mounts", "r");

	if (fp == NULL)

		return NULL;



	while (fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",

		      debugfs_mountpoint, type) == 2) {

		if (strcmp(type, "debugfs") == 0)

			break;

	}

	fclose(fp);



	if (strcmp(type, "debugfs") != 0)

		return NULL;



	ret = find_mountpoint("debugfs", (long) DEBUGFS_MAGIC,

			      debugfs_mountpoint, PATH_MAX + 1,

			      debugfs_known_mountpoints);

	if (ret)

		debugfs_found = true;



	return debugfs_mountpoint;

	return ret;

}



/* mount the debugfs somewhere if it's not mounted */

tools/lib/api/fs/debugfs.h

+1 −10
Original line number Diff line number Diff line 
#ifndef __API_DEBUGFS_H__

#define __API_DEBUGFS_H__



#define _STR(x) #x

#define STR(x) _STR(x)



/*

 * On most systems <limits.h> would have given us this, but  not on some systems

 * (e.g. GNU/Hurd).

 */

#ifndef PATH_MAX

#define PATH_MAX 4096

#endif

#include "findfs.h"



#ifndef DEBUGFS_MAGIC

#define DEBUGFS_MAGIC          0x64626720

tools/lib/api/fs/findfs.c

0 → 100644
+63 −0
Original line number Diff line number Diff line 
#include <errno.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <stdbool.h>

#include <sys/vfs.h>



#include "findfs.h"



/* verify that a mountpoint is actually the type we want */



int valid_mountpoint(const char *mount, long magic)

{

	struct statfs st_fs;



	if (statfs(mount, &st_fs) < 0)

		return -ENOENT;

	else if ((long)st_fs.f_type != magic)

		return -ENOENT;



	return 0;

}



/* find the path to a mounted file system */

const char *find_mountpoint(const char *fstype, long magic,

			    char *mountpoint, int len,

			    const char * const *known_mountpoints)

{

	const char * const *ptr;

	char format[128];

	char type[100];

	FILE *fp;



	if (known_mountpoints) {

		ptr = known_mountpoints;

		while (*ptr) {

			if (valid_mountpoint(*ptr, magic) == 0) {

				strncpy(mountpoint, *ptr, len - 1);

				mountpoint[len-1] = 0;

				return mountpoint;

			}

			ptr++;

		}

	}



	/* give up and parse /proc/mounts */

	fp = fopen("/proc/mounts", "r");

	if (fp == NULL)

		return NULL;



	snprintf(format, 128, "%%*s %%%ds %%99s %%*s %%*d %%*d\n", len);



	while (fscanf(fp, format, mountpoint, type) == 2) {

		if (strcmp(type, fstype) == 0)

			break;

	}

	fclose(fp);



	if (strcmp(type, fstype) != 0)

		return NULL;



	return mountpoint;

}

tools/lib/api/fs/findfs.h

0 → 100644
+21 −0
Original line number Diff line number Diff line 
#ifndef __API_FINDFS_H__

#define __API_FINDFS_H__



#define _STR(x) #x

#define STR(x) _STR(x)



/*

 * On most systems <limits.h> would have given us this, but  not on some systems

 * (e.g. GNU/Hurd).

 */

#ifndef PATH_MAX

#define PATH_MAX 4096

#endif



const char *find_mountpoint(const char *fstype, long magic,

			    char *mountpoint, int len,

			    const char * const *known_mountpoints);



int valid_mountpoint(const char *mount, long magic);



#endif /* __API_FINDFS_H__ */